It's not always enough to know what's "trending." It kind of helps to know why. Welcome to The Social Climber, where we provide a quick primer on the people, places and things that are being feverishly searched and shared online -- and try to make sense of it all.

1

Fallon and Timberlake Take Down #Hashtags

NBC

#Awesome! #HILARIOUS!!! In a skit on his late night talk show with pop superstar Justin Timberlake, Jimmy Fallon had a conversation where they tweeted out loud, and made all us tweeters sound like idiots. The duo's entire conversation about what they did that day was punctuated with the word hashtag -- the overused #-sign found, and misused, in oh-so-many tweets.

That that, #twits!

2

Ex-Charger Paul Oliver Found Dead

Getty Images

Sad news came from the sports world today as former Chargers safety Paul Oliver was found dead at his Georgia home. The 29-year-old died Tuesday night from a gunshot wound, Cobb County police told ABCNews.com.

3

Super Rare Lincoln Photo Revealed!

Alexander Gardner/Library of Congress

Where's Abraham Lincoln? There he is! Former Disney animator Christopher Oakley made an awesome discovery of the actual Honest Abe in an old photo from the Gettysburg address.

The historian announced Tuesday that improved technology helped him spot the real Lincoln in the photo, and told Smithsonian magazine that the man who amateur historian John Richter originally spotted as the 16th president was nothing more than a tall, top-hat donned doppelganger.

4

Long Island Mall, Schools Locked Down After Shooting

Nassau County Police

Police are hunting for a man who walked into a lighting company on Long Island Wednesday and shot two people, killing one. A mall and school were under lockdown after the shooter, who Nassau Police Chief Steven Skrynecki said was a "disgruntled ex-vendor" of Savenergy Inc., shot the company's owner and an employee.

5

Stamp Cost to Rise, Again?

Andrew Burton/Getty Images

There seem to be a few things that are constant throughout life: death, taxes, and the ever-rising cost of stamps. For those of you who are still using snail mail, the latter in that trio is happening again, as the money-losing U.S. Postal Service is seeking to raise the first-class stamp cost by 3 cents to $0.49, the postal Board of Governors said Wednesday.

So it's time to either break open those savings accounts, or finally learn to attach a file to an email.